a clear trendp < .01
Since the 1950s, the δ 15 N Phe values in harp seal teeth from the Barents Sea showed a clear trend of −0.36 ± 0.01 ‰ decade −1 (linear model: p < .01, R 2 = 43.1%, F = 54.8, n = 72, Data S1 , Figure S2 and Table S1), declining from 11.7 ± 1.0 ‰ in 1951–1952 to 10.0 ± 0.2 ‰ in 2011–2012 (Figure 1c ). 3.2 Simulated trends At the Barents Sea Opening (20°E between Norway and Svalbard), our model predicted that the average δ 15 N NO3 values of inflowing Atlantic Water (potential temperature >2°C; salinity >34.5 psu) decreased by −0.08 ± 0.00 ‰ decade −1 from 1970 to 2019 (Figure 2a ).